Apparatus for heat-treatment



1946. H. A. STRICKLAND. JR

I APPARATUS FOR HEAT TREATMENT 2 Sheets-Sheet 1 Filed June 21, 1943 TOEM INVENTOR MA 8% p JIM j ATTORNEY Jul-1e 1946- H. A. STRICKLAND, JR 2,402,509

I APPARATUS FOR HEAT TREATMENT .2 Sheets-Sheet 2 Filed June 21, 1943 him I Jim INVENTOR I ATTORNEY Patented June is, 1946 APPARATUS FOR HEAT-TREATMENT Harold A. Strickland, Jr., Detroit, Mich, assignor, by mesne assignments, to Budd Wheel Company', a corporation of Pennsylvania Application June 21, 1943, Serial No. 491,694

2 Claims. 1

This invention relates to apparatus for applying heat treatment by electrical induction to wheels and other products.

In the heat treatment of metal products by inductive methods, it is frequently desirable to limit the extent of heat application to predetermined areas. In the case of wheels, for example,

it may be desirable to heat treat the periphery thereof without disturbing the web or interior supporting structure.

Among the objects of the present invention is the provision of means for heat treating an annular edge area without internal modification of the interior supporting web. An object also is to provide inductive heating means that may be applied to a circular object in an annular area intermediate the edge and center. Still another object is to effect heat treatment on an integral metal wheel structure without producing axial distortion of the metal. An object also is to Provide effective quenchin means without disturbing the requisite proximity of treated area and heat producing coils. Additional objects pertain to a new wheel structure having radial rigidity combined with limited axial flexibility; to quench apparatus effective in quenching closely placed surfaces susceptible to steam pocket formation; to induction heating apparatus arranged for quick handling of articles intended for heat treatment; and in general a unified, and eflicient assembly of induction'heating structure.

An arrangement of apparatus and a specific form of product, which may be preferred, is described in thefollowing specification and shown in the accompanying drawings,-in\which Fig. 1 is a side elevation in part section of the heating apparatus including also a section of a wheel inserted for treatment;

Fig. 2 is a plan view of the apparatus with the wheel and wheel lock'removed;

.Fig. 3 is a detail section showing inand outleads for electrical and cooling media;

Fig. 4 is a detail section showing a coil support; and i Fig. 5 is a detail showing a modified quenching apparatus.

Referring particularly to Figures 1 and 2, there is disclosed an inductive heating apparatus intended primarily for the heat treatment of circular bodies or articles such as wheels, rims and the like. On the base plate III is mounted by supports II the motor flange generally indicated by the numeral I2. The base plate III is in the general shape of a flattened disc and is hollow in sections to form a reservoir [5 for the quenching fluid :3, the inlet pipe connection to the reservoir of the base plate being at ll. There is attached at the base periphery the upwardly, ex-

tending front and side flange l6 forming with the back plate I! a pan-shaped receptacle for quench fluid after egress from the quenching nozzles. .The back plate, ll is adapted to extend above the heating apparatus and forms a support for the transformer (not shown), lead in bus bars and other auxiliary equipment forming a, part of the complete heating apparatus assembly. The flange [6 is attached to the base section of the I base plate by means of bolts l8.

The central section of the base plate i2 is apertured and extended on the upper side in a. tubular support member I! internally threaded at its upper end. Positioned within the tubular member [9 is a work support generally indicated by the numeral 20. This supportincludes a stub shaft 2! positioned within the tubular member l9 and supported therein by means of ball bearing units at the upper and lower ends of the tubular support l9. To provide for the ball bearing connection as mentioned, the support It at its upper end is formed with angular-recesses 22 and 23, the recess 22 being adapted to receive a ring shaped bearing 24 having ball bearing runways formed therein and adapted in conjunction. with a smaller ring 25 fixed on shaft 2!, having outwardly formed runways therein to hold ball bearings 26 in operative relationship. The ring 25 is mounted on a section of the stub shaft H of reduced diameter, the edge formed by this section supporting the ring 25 in position. Immediately above the ring 22, in screw threaded engagement with the end surface of the tube I9 is a nut 21 which is adapted to hold the ring '22 in fixed position upon the end of the tube l9.

The lower end of the stub shaft section II is supported with reference to the base plate In by means of the ball bearing unit M including the runway rings 8i and 62 and ball bearings 63. The ring Si is fastened directly to the shaft and the ring 62 is secured in position by the locking wire 64. The stub shaft 21 is apertured on its lower end to receive an operating shaft 65.

Fixed to the shaft it directly above the inner ring 25 is a circular work support plate having an annular edge extension beyond the external boundary of the supporting tube 19. Skirt II is fastened to the underside of the plate 30, the sameenclosing the support is and extending to and adjacent the base plate lll. Directly above plate 30 is positioned the work centering head I l,

the same being in the shape of a short cylinder provided with bayonet slots 32 on the periphery thereof. This head is held in position on the shaft by means at the terminal nut 34 which is screw threaded to the end of the shaft 2! and holds the head and various other units securely on the shaft end. A washer 33 separates the nut 34 from the head 3i.

Means are provided for clamping the work piece in position on the work centering head ii in the work clamping member 40, the latter comprises a ring (I provided with pins 42 adapted to move into, and be secured by the bayonet slots 22. The ring ll is connected to the top clamp section 43 by means of bolts 44 spaced from the ring 4| by means of tubular spacers 45.

The work piece as illustrated in Figure 1 of the drawings and which is adapted for heat treatment by the described apparatus is a sheet metal wheel ill, commonly referred to in the trade as a bogie wheel, a primary purpose of which is to serve as a guide wheel for heavy traction and automotive apparatus such as tanks and which consequently are subjected to severe treatment in use. Ordinarily these vessels undergo heavy radial, axial or lateral stresses so that not only must the bearing rim of the wheel be sufficiently hard to resist road impacts and nicking, but also the web or body of the wheel must possess sufficient elasticity or resiliency to permit lateral yielding when the wheel is subjected to severe lateral stresses. As illustrated this wheel consists of a single metal disc, the same having a flattened hub section, a peripheral road bearing section having hardened metal areas and an intermediate sigmoid section joining the hub and edge sections. Preferably the hub section Si is formed with apertures annuiarly displaced adapted to receive the heads of studs 02, the latter being threaded into apertured extensions 54 formed about the edge of the support plate 30. These studs serve as direct supporting means for the wheel upon the plate 30. The sigmoid section It includes two reversely curved annular segments connected by a flattened area, the same being approximately S-shaped. The edge section 56 is of approximately V-shape with the V opening toward the hub of the wheel. One segment of the V, 51, joins the sigmoid and is inclined angularly relative to the radial hub section. The other segment SI of the edge section also is inclined relative to the hub section, forming a reversely turned rim for the wheel. As described to this point, it is apparent that the wheel may be mounted upon the rotatable stub shaft 2| upon which it is radially secured by means of the support plate In, the centering head II and the clamping member 48.

Heat means II for the work piece is provided in a single turn inductor 01 which is supported from the base plate II by standards ll connected through insulation I! to the inductor lugs I! in the shape of a hollow tube adapted to receive and transmit the cooling fluid 08. One face ll of the inductor tube is flattened and angular-1y positioned with reference to the base plate Ill so as to lie in acute angular relationship to the edge section of the-heating coil. The ends of the single coil 01 are led outwardly as shown particu-- lady in Figure 3.to form terminals and 'Il.

These brackets are also provided with ducts I1 which communicate with the terminals as shown in Figure 1.

, Quenching means for the heating apparatus is provided by a plurality of annularly displaced stand pipes so which at their bases communicate with the reservoir I! in the base plate ill in the area intermediate the stub shaft 2| and the standards 1B. The outlet ends of these stand pipes 80 terminate adjacent the inner edge of the inductor coil 61 and adjacent these ends the pipes are provided with outwardly positioned spray nozzles of such shape as to throw under pressure a fan shaped stream of fluid into the space between the flattened edge 88 of the inductor 51 and the adjacent flattened segment 51 oi. the workpiece. It is pointed out as shown in Figure 1 that the spray consequently moves in a plane parallel and adjacent to the surface of the wheel section 51. It is noted further that there is a divergence between the adjacent surfaces 51 and 69 of wheel and inductor in an outward direction so that a degree of Venturi action develops on t 1 outward moving stream of quench fluid. Obviously, when the wheel is rotating at a high speed, there is added to the normally radial outward pressure acting on the fluid, a centrifugal force due to the wheel rotation, so that the tendency to force the fluid by the adjacent wheel surface is pronounced.

In the operation of the heat treatment apparatus the workpiece such as the wheel illustrated is placed in position and rotative power applied. Alternating currents are then led into the inductor circuit, which may be of a frequency in the order of 3000 cycles. The inductive action of the current in the inductor coil 61 heats the adjacent surface 51 of the wheel to a temperature above the critical point for the metal at which temperature it is preferably held a short time period such as five seconds depending on the characteristics of the steel; after which with the wheel still rotating the quenching fluid is applied. As previously mentioned the normal pressure of the fluid combined with the Venturl effect and the centrifugal rotatlve action of the wheel causes rapid out-flow of fluid which is normally of sufficient force to prevent the formation of steam pockets. This rapid flow of cooling fluid rapidly reduces the metal temperature, a time period of six seconds being usual for a wheel as described. and imparts to the metal section 51 a desired degree of hardness. It is noted that the control over the degree of hardness may be secured either by control of the force of the quenching nozzles or by the degree of maintenance of the current in the inductor coil during the initial quenching operation.

A wheel made according to the described process possesses adequate edge hardness for resistance to impact and at the same time yields in the web so as to absorbradial and axial shock stresses.- It is pointed out that the wheel is readily and firmly placed into and out of podtion; that the rotatable mount insured a uniformity in both head and quench; and that through the hydraulic head as well as the centrifugal force of rotation the spray quench is forced quickly by the juxtaposed surfaces insuring a reduced formation of static steam pockets.

Figure 5 illustrates a modifled form oi q e ching apparatus nozzle and inductor heating surface. In this modification instead of a slit nozzle stand pipe ll a tubular nozzle II project: outwardly at an angle indirect line with the anacon- .5 plane of the section 51 of the wheel to be heated, the nozzle terminating approximately at the inner edge of the inductor coil 9!. face 82 of the coil 9| instead of being formed with a uniform fluid surface includes a curved section 93 forming an oflset between a lower flat section and a higher flat section 85, the inclination of the flat surface 94 and being approximately vthe sameand the curvature of the section 815 of the inductor being approximately the same' as theadiacent edge section, of the wheel. With this arrangement it is possible to force the quench fluid between-inductor 3 and wheel surface withgre'ater velocity and to extend the hardened area of thewheel to a point nearer an extrem'eouter edge of the same.

While the term wheel" is used with rei'erence to the specific showing of thedrawings, it is understood that in the claims-the meaning is broadened to include any disc-like article subject to similar methods of heat treatment.

Modifications of the invention other than that shown may of course be made and no limitation therefore is intended in the described embodiments. other than that which'is required by the scope of claims hereto appended. Y

What is claimed is:

1. A heat treating apparatus for annular metallic wheel sections comprising vaninduction coil having an annular heating surface, rotat able means for 'supporting'the wheel coaxially with respect to the heating suriace of said coil The pipe surand with the annular wheel section arranged parallel to and spaced from said heating surface to form an annular clearance space therebetween extending in a generally radial direc tion relative to the axis of saidheating surface and said wheel, quenching means for directing I quenching fluid into said annular space in a genclearance space.

orally outward radial direction, and means for rotating said support whereby the centrifugal force is-added to the initial velocity of the quenching. fluid in forcing the same through said 2. A heat treating apparatus for annular metallic wheel sections comprising an induction coil having an annular heating" surface, rotatable means for supporting the wheel coaxially with respect to the heating surface of said coil and with the annular wheelsection arranged parallel to and snaced from said heating surface to and over the 

